Roller conveyors are known and typically include at least one powered or motorized roller and a plurality of idler or freely rotating or slave rollers. The idler rollers are driven via the powered roller and a plurality of O-rings or bands around adjacent rollers. For example, the powered or motorized roller may be positioned between two idler rollers and may be connected to and may drive the adjacent idler rollers via respective O-rings, while the adjacent idler rollers each may in turn be connected to and drive a second or adjacent idler roller via another O-ring, and so on along a zone or set of rollers of a roller conveyor.
Typically, as each O-ring is driven by one roller and drives the adjacent roller, a reduction in torque or power may occur at the interface of the O-ring on the rollers, such as a reduction of approximately 5% of the torque or power provided by the first roller. This reduction in power or torque may occur at each O-ring interface, such that additional power is typically lost at each idler roller toward the outer ends of the zone and away from the motorized roller. Accordingly, the two idler rollers adjacent to the motorized roller may have a torque or power reduction of approximately 5%, while the ends of a zone driven by a particular motorized roller may have substantially reduced power. Also, the end of the zone may be positioned adjacent to another end of an adjacent zone having substantially reduced power at the ends, such that several adjacent rollers may have reduced torque or power capabilities and, thus, may define potential stall areas along the conveyor. Also, because of the reduced power in certain areas of the roller conveyor, such conventional O-ring roller conveyors may have limited speed capability, and may be limited to conveying articles at approximately 150 feet per minute or thereabouts.
The reduction in torque or power at each interface of the O-rings and rollers may be increased if the rollers are skewed so as to convey articles or justify articles toward one side of the conveyor. In such applications, the rollers may have less torque or power capability away from the motorized roller and, thus, may be prone to have articles stall at the ends of the zones of the conveyor.
Therefore, there is a need in the art for a roller conveyor which overcomes the shortcomings of the prior art.